What conditions is lanthanum used to treat?

Lanthanum Use in Clinical Medicine

Lanthanum carbonate is primarily used to treat hyperphosphatemia in patients with chronic kidney disease, particularly those on dialysis, as a non-calcium, non-aluminum phosphate binder. 1, 2

Mechanism of Action

• Lanthanum is a lanthanide metal (atomic number 64) that works by binding to dietary phosphate in the gastrointestinal tract
• Forms insoluble lanthanum phosphate complexes that prevent phosphate absorption
• Has minimal systemic absorption, with most of the drug being excreted in feces 1, 3

Clinical Indications

Primary Indication

• Hyperphosphatemia in chronic kidney disease (CKD):
  • Particularly in CKD G5D (dialysis-dependent) patients 1
  • Used when serum phosphate levels are progressively or persistently elevated 1
  • Often used as second-line therapy after calcium-based binders 4

Patient Selection

• Most beneficial in:
  • Patients who have failed calcium-based phosphate binders
  • Patients at risk for hypercalcemia
  • Patients with concerns about vascular calcification 1, 2

Dosing and Administration

• Dosage range: 375-3000 mg/day of elemental lanthanum 2, 5
• Initial dose: 375-750 mg/day, typically divided with meals 2
• Administration: Should be taken with or immediately after meals to maximize phosphate binding 2
• For hemodialysis patients: The American Society of Nephrology recommends administering lanthanum after hemodialysis on dialysis days to avoid premature elimination 2

Titration Protocol

1. Start: 375 mg/day with main meals
2. Week 1: Evaluate serum phosphate levels
   • If phosphate >1.80 mmol/l: Increase to 750 mg/day
   • If phosphate ≤1.80 mmol/l: Maintain dose
3. Week 2-4: Continue weekly evaluation and titration
   • Maximum dose: 3000 mg/day (divided into 3 doses) 2, 5

Efficacy

• Approximately 70% of patients can achieve serum phosphate ≤1.80 mmol/l with proper titration 5
• Comparable efficacy to other phosphate binders in controlling serum phosphate levels 6
• In CKD G3b and G4 (pre-dialysis), lanthanum did not increase likelihood of arterial stiffness or vascular calcification compared to placebo in the IMPROVE-CKD trial 1

Monitoring

• Serum phosphate: Weekly during titration, monthly once stabilized 2
• Serum calcium: Regular monitoring to assess for potential hypocalcemia 2
• Calcium-phosphorus product: Regular evaluation 2

Adverse Effects

Common

• Gastrointestinal disorders:
  • Nausea, vomiting, diarrhea, constipation, abdominal pain 6
• Headaches 6

Concerning

• Lanthanum deposition in tissues:
  • Gastric mucosa (lanthanum gastropathy) 7
  • Bone accumulation (though no evidence of bone toxicity) 1, 6
  • Potential CNS effects (seizures, encephalopathy) 6

Advantages Over Other Phosphate Binders

• Does not contain calcium (reduces risk of hypercalcemia)
• Does not contain aluminum (avoids aluminum toxicity)
• May be cost-effective as second-line therapy, particularly in pre-dialysis patients 4

Cautions and Contraindications

• Drug interactions: May reduce bioavailability of drugs with anionic groups (tetracyclines, quinolones, levothyroxine) 3
• Limited data on long-term safety beyond 2 years 6
• Concerns about tissue accumulation, particularly in bone and potentially brain 6

Place in Therapy

Lanthanum carbonate is typically used as an alternative phosphate binder when:

1. Calcium-based binders are contraindicated (hypercalcemia)
2. Concerns exist about vascular calcification
3. Patients have failed first-line phosphate binders 1, 2, 4

According to KDIGO guidelines, decisions about phosphate-lowering treatment should be based on progressively or persistently elevated serum phosphate, and the dose of calcium-based phosphate binders should be restricted in adult patients with CKD G3a to G5D 1.